Some people hear music perfectly well and get little pleasure from it. They can tell you that a piece is meant to be sad, or happy. They don't feel much of it. Robert Zatorre is a neuroscientist at McGill University in Montreal, and he helped describe them. He told the CBC that many of them try to hide it. His example was a party with music blaring. They'd go along with it, he said, and "try to pretend that they liked it as much as everyone else did."
Most people get something from music that these listeners don't, and sometimes it shows on the skin. A favorite piece reaches a certain moment, and a shiver runs down your spine, or you get goosebumps. These are chills. For a given listener, they often come at the same spot in the same piece. Not everyone gets them.
The people at the party hear the same notes you do. Something happens in you that doesn't happen in them. What happens in your brain when music gives you chills? And why should a run of notes feel good at all? Food keeps you alive, and money buys food. Music's use, if it has one, is far less obvious.
The last lecture left a gambler waiting to be paid. It argued that your brain bets on every next note, by odds it picked up just from listening. David Huron, the music scholar from that lecture, argues that the brain rewards a correct prediction. If he's right, something in the brain should be doing the paying. This lecture goes looking for it.
The search takes four steps. The first catches a chill in a brain scanner, to see what answers it. The second winds back fifteen seconds, to something that starts before the chill does. The third pushes on that machinery, with drugs and with the people from the party. The fourth asks what the machinery is paying for, and whether pleasure is even the right word for what it does.
A chill is handy for science because you can time it, and the body shows it. Researchers treat a chill as a marker: a burst of the body's arousal at a peak of pleasure. Chills aren't required. In one scan, pleasure without chills moved the same brain regions, only less.
This is the study the course began with. In 2001 Anne Blood and Zatorre scanned ten students at McGill, using a machine that tracked blood flow in the brain. All ten were trained musicians, chosen because certain pieces gave them chills reliably. Each brought one classical piece. Among them were Rachmaninoff's Third Piano Concerto and Barber's Adagio for Strings. Each student's chill piece doubled as another student's dull one, so only the listener changed. The Barber that gave one student chills was dull to the student who brought the Rachmaninoff.
With their own pieces, the students reported chills in 77 percent of the scans. With somebody else's, never. Blood flow rose in several regions as the chills grew stronger, and fell in others, one of them tied to fear. Among the regions that rose were parts of the reward system. It's an ancient circuit. Its job is to make an animal repeat what keeps it and its kind alive, such as eating, sex and caring for young. In people it answers to money as well. A small region near its center is called the nucleus accumbens. I'll call it the reward hub. One region that rose sat right where the hub is, though this scanner was too coarse to be sure it was the hub. Blood and Zatorre noted that food, sex and drugs like cocaine work the same regions, though that says nothing about how strongly.
But blood flow can't name the chemical at work. The reward system runs partly on dopamine, a chemical messenger. Dopamine released there can make an animal more likely to repeat what it just did. Valorie Salimpoor worked with Zatorre at McGill, and she set out to see whether music releases it. She screened people who answered advertisements. Each sent in pieces that gave them chills, from classical and jazz to punk, techno and tango. She kept the ones whose chills could be counted on. Their chills had to come at the same point every time, and not because the music brought back a memory.
Her scan used a radioactive tracer that competes with dopamine for the same docking points on nerve cells. Released dopamine crowds the tracer out, so a weaker tracer signal means more dopamine. The scan can only see the deep core of the reward system, where the hub sits. There, their own music released more dopamine than neutral music did. The biggest changes were in the hub and in the region just above it, called the caudate. Two people's scans were discarded, so the result rests on eight. A run of notes, then, can reach the chemistry that food and money reach.
Salimpoor's next question was about timing. Her team scanned the same people again, with a machine that follows blood flow from moment to moment. This one can't see dopamine. Each listener pressed a button whenever a chill came. The team watched only the spots that had released dopamine in the first scan. They asked what those spots were doing in the run-up, the fifteen seconds before each chill. That window was set in advance, from earlier work showing that the body's arousal starts climbing about then.
The obvious guess is that the reward system is busiest at the chill itself. The hub did peak at the chill. But the caudate rose earlier, and more, during the run-up, then dropped back once the chill arrived. The hub rose in the run-up too, and kept climbing. The first scan fit this pattern. People who had more chills, and so more run-ups, had released more dopamine in the caudate. People whose chills were stronger had released more in the hub. Part of the reward system works while the moment is still on its way.
There's a reason a reward system would get to work before the reward. Much of its job is prediction. It learns which signals come before something good, and those signals become rewarding in themselves. Its response also grows when an outcome turns out better than expected. Salimpoor's team suggests that the notes leading up to a peak can work that way. They tell the brain the best part is near.
The team called the two stages anticipation and the peak. They suggested the two might match what reward researchers call wanting and liking. Wanting is the pull toward a reward that's on its way. Liking is the pleasure when it arrives. The team pointed out that composers and performers work the anticipation hard. They hold back what you're waiting for, with an unexpected note or a slower tempo, to make you want it more. In the last lecture's terms, the caudate works while the chips are on the table, and the hub when the moment arrives.
These listeners knew their pieces well, though, so they knew a chill was coming. Their run-up might come from memory of one piece, or from a feel for how music in general goes. The team said later experiments would have to tell the two apart.
So far, then, the reward system answers to music. Dopamine is released in it, and part of it works in the run-up. All of this is watching, though. A system that lights up with the pleasure might only be along for the ride.
To show the reward system makes a difference, you have to push on it. A group in Barcelona did that in a drug study, with Zatorre on the team. Healthy volunteers came to a drug-research unit at a Barcelona hospital three times, at least a week apart. Each time they swallowed a single capsule. One held levodopa, a drug that nerve cells turn into dopamine, with a second drug that slows its breakdown outside the brain. One held risperidone, which blocks some of the places where dopamine docks. One held milk sugar. Neither the volunteers nor the researchers knew which was which. An hour later the volunteers heard pop songs and favorites of their own, rating their pleasure with buttons, from none up to chills. They could then buy each pop song with their own money, at one of four prices from nothing to a euro and 29 cents.
Some volunteers got chills even on the milk sugar. Compared with the sugar, those listeners spent 65 percent more time in chills on levodopa, and 43 percent less on risperidone. Their skin's response at moments of high pleasure rose and fell the same way, and so did their bids. They offered more for the songs on levodopa than on risperidone. The firmest result was the gap between the two drugs. Their other judgments held steady. The drugs didn't change how happy or sad the music seemed, or how calm or rousing, or how familiar.
These were single doses, given to healthy volunteers for a study. They say nothing about people who take these medicines for an illness. Risperidone also blocks receptors for serotonin and other messengers. So I'd hold open the chance that part of the drop on risperidone wasn't dopamine's doing. Still, the authors say no study before had changed dopamine directly and shown musical pleasure following. Earlier work had mostly watched. This one pushed, and the pleasure moved. The ratings people gave after each song moved the same way, though too weakly to be sure of.
The people from the party come next, and a 2013 study from Zatorre's lab shows why they matter. People heard music they had never heard before, and could bid to buy it. The hub was busier for the pieces people bid more for. The brain's hearing areas were busy for every piece alike. These are the areas in and around the hearing cortex. What changed was how closely they rose and fell with the hub. For pieces worth more to someone, the two moved together more closely. Zatorre and Salimpoor think the hearing areas hold templates, stored patterns of how music tends to go, built from a lifetime of listening. They suggest that some of that knowledge comes from the statistical learning of the last lecture, the brain's silent counting of what follows what. In their view, the hub sets a value on what those templates predict.
That line from hearing to reward suggests a test. Somewhere there should be people in whom it's weak. The Barcelona group found them. They gave a questionnaire about music and pleasure to more than a thousand university students, and picked ten of the lowest scorers. They compared them with ten average listeners and ten keen ones. The low scorers weren't depressed, and they enjoyed other things normally. They did as well as anyone on a test for amusia, the failure to make sense of music from the second lecture. They could tell happy music from sad, scary or peaceful music. In the other listeners, heart rate and skin response climbed with their pleasure. Zatorre said the low scorers' responses "more or less flatlined." In a game for money, their bodies responded like anyone's. The group named the condition specific musical anhedonia. Anhedonia is a loss of pleasure, and here the loss is for music alone.
It's found in people who are otherwise well, and a year later the low scorers' ratings held. That's different from losing pleasure in music you used to love. The US National Institute of Mental Health lists "loss of interest or pleasure in hobbies and activities" among the signs of depression.
Later the group scanned fifteen people of each kind. In all three groups, the hearing areas answered music the same way. In the low scorers, the reward hub answered music weakly, and a gambling game normally. Their right-side hearing areas also moved less closely with the hub than in the keenest listeners. Their hearing works, and their reward system works. What seems weak is the line between them.
One caution covers these studies. Most are small, from eight people to forty-five. All of them come from one circle of labs working together, in Montreal and Barcelona. Other labs have also found the reward system answering to music, but the dopamine and anhedonia work is that circle's. Together they point to a reward system that matters to the pleasure, working in step with the hearing areas.
What is the reward system paying for? Here the last lecture's program comes back, with its two numbers. Uncertainty is how thinly the program spreads its chips before a note. Surprise is how little it staked on the note that came. An old idea says people like things best at a middling level of complexity. Too simple bores, and too tangled baffles. On that idea, enjoyment plotted against complexity makes a hump, an upside-down U, with a sweet spot at the top. A 2017 review of 57 studies counted most of them as compatible with some form of the hump. Benjamin Gold and colleagues at McGill read the same review more harshly. By their count only 15 showed the hump, and each study had measured complexity its own way, so they called the evidence mixed.
Gold's team used the program instead. Zatorre was on the team, and so was Marcus Pearce, the cognitive scientist in London who built it. The program scored real melodies, played one note at a time on a computer flute, for their average uncertainty and average surprise. Listeners rated how much they liked each melody they didn't recognize. Enjoyment rose and then fell. People liked best the melodies in between, and mostly liked the predictable ones more than the least predictable.
A separate team, which also included Pearce, took the idea down to single chords. Its copy of the program learned the chords of hits from the Billboard Hot 100. The team took chord sequences from those songs and stripped out the melody and rhythm. They moved them all into C major, so nobody could recognize a song. Listeners rated each chord's pleasantness on a slider as it played. Pleasure depended on uncertainty and surprise together. A surprising chord pleased when the next chord had been easy to call, as near the end of a section. An unsurprising chord pleased when the next one had been hard to call, as in an unusual sequence.
In the gambler's terms, people enjoyed a confident bet that lost. The chips were piled on one chord, and a different one came. They also enjoyed an uncertain bet that came in. The chips were spread thin, and one of the likelier chords came. Gold's team read their melody results as a reward for learning. Confirming a shaky guess teaches you something. So does losing a confident one, if the chord that came still makes sense. A dead certainty teaches nothing, and neither does noise. The last lecture's guess was that the brain rewards a correct prediction. On Gold's reading, it also rewards a mistake you can learn from.
The chord study had a second half, in a scanner. The pattern of pleasure showed up in the hearing areas, and in regions tied to emotion and memory. The reward hub didn't follow surprise at all. It followed only uncertainty, working harder when the next chord was hard to call. The team read that as the hub supplying the wanting, the pull toward whatever will settle the uncertainty. That moves the hub to the other side of Salimpoor's two stages. Her team had suggested its peak might be the liking. This reading makes it the wanting, and the reading has a history.
In 1989 the psychologist Kent Berridge and his team expected that wiping out nearly all of a rat's dopamine would dull its pleasure in sugar. They read that pleasure from the rat's face. Rats relax their faces and move their tongues in a rhythm at a sweet taste, and gape at a bitter one. The rats with almost no dopamine stopped eating on their own altogether. Yet their faces at a taste of sugar were completely normal. Berridge concluded that dopamine drives wanting, not liking. On their account, the liking comes from tiny hotspots worked by other chemicals. Opioids are among them, the brain's own heroin-like signals. In a rat, the hotspot in the reward hub is about a tenth of the hub. The rest of the hub can drive wanting but not liking. On that account, the hub's peak at a chill could be wanting at its height. Berridge wrote that in the 1990s this was "a lonely scientific position." He says few researchers who study reward still claim dopamine is the pleasure.
The Barcelona drug study was built to test exactly this. It counted the pleasure buttons as liking and the bids as wanting. Suppose dopamine drove only wanting. Then the drugs should have moved the bids and left the buttons alone. Both moved. The Barcelona team still allows another reading. Dopamine may be a step the pleasure can't do without, while opioids further along make the pleasure itself. Studies that blocked opioids have dimmed musical pleasure in some listeners. One of them dimmed unpleasant music too, which muddies it, and two later studies didn't repeat the effect on pleasure. In 2025 a team in Finland scanned fifteen women listening to music they had chosen for pleasure. More chills went with signs of more opioid release in the hub. Comparing music with silence overall, though, the authors couldn't tell whether opioid activity rose or fell. I find the firm part narrower than either side's claim. Dopamine changes how much people enjoy music, and how much they want more of it. Nobody can yet say whether dopamine is the enjoying itself.
Why does music give you chills? A chill marks a moment when the reward system that handles food and money answers your brain's bets about the music. Part of that system starts work in the seconds before the big moment, while the bet is still riding. Its hub peaks as the moment lands. In a study, turning dopamine up or down moved both the time spent in chills and the price people would pay. With music nobody had heard before, the hub still tracked what people would pay. Their liking still followed the program's odds. So memory of one piece can't be the whole story. The people at the party hear all of it. In them, the hearing areas and the hub barely work in step.
And why should a run of notes feel good at all? Gold's team offers an answer: the brain rewards learning, and music offers plenty of predictions to confirm and to break. By people's own ratings, music pleases most when you can bet on it and still be beaten by it. What dopamine adds is still argued. It may carry some of the pleasure itself, or only the wanting that comes before it. I suspect the two are hard to separate in music, where so much of the pleasure lies in what's coming.
The bets in this lecture were all about which note or chord comes next. Music also sets up bets about when. Even the 2001 chills scan caught activity in parts of the brain that handle movement. Why does a beat make you want to move, even when you're sitting still?